CPU: remove AVX code, switch to __builtin for AES detection (#1959)

* [cpu] remove avx detect and code blocks, try to switch to __builtin
* [cpu] use __builtin_* only on x86 systems
* [cpu] perform check in separate function
* [cpu] set AES definition on MSVC
* update x86 and aes support checks at compile time
* [cmake] update comment about AES on MSVC

Author: r4sas

.editorconfig

@@ -34,3 +34,6 @@ trim_trailing_whitespace = false
 [*.yml]
 indent_style = space
 indent_size = 2
+
+[*.patch]
+trim_trailing_whitespace = false

build/CMakeLists.txt

@@ -197,14 +197,11 @@ endif()
 
 # Note: AES-NI and AVX is available on x86-based CPU's.
 # Here also ARM64 implementation, but currently we don't support it.
-# MSVC is not supported.
-if(MSVC)
-  message(STATUS "AES-NI is not supported on MSVC, option was disabled")
-  set(WITH_AESNI OFF)
-endif()
-
+# MSVC is not supported due to different ASM processing, so we hope OpenSSL has its own checks to run optimized code.
 if(WITH_AESNI AND (ARCHITECTURE MATCHES "x86_64" OR ARCHITECTURE MATCHES "i386"))
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -maes")
+  if(NOT MSVC)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -maes")
+  endif()
   add_definitions(-D__AES__)
 endif()
 

contrib/i2pd.conf

@@ -280,8 +280,6 @@ verify = true
 [cpuext]
 ## Use CPU AES-NI instructions set when work with cryptography when available (default: true)
 # aesni = true
-## Use CPU AVX instructions set when work with cryptography when available (default: true)
-# avx = true
 ## Force usage of CPU instructions set, even if they not found (default: false)
 ## DO NOT TOUCH that option if you really don't know what are you doing!
 # force = false

daemon/Daemon.cpp

@@ -150,12 +150,11 @@ namespace util
 
 		bool precomputation; i2p::config::GetOption("precomputation.elgamal", precomputation);
 		bool aesni; i2p::config::GetOption("cpuext.aesni", aesni);
-		bool avx; i2p::config::GetOption("cpuext.avx", avx);
 		bool forceCpuExt; i2p::config::GetOption("cpuext.force", forceCpuExt);
 		bool ssu; i2p::config::GetOption("ssu", ssu);
 		if (!ssu && i2p::config::IsDefault ("precomputation.elgamal"))
 			precomputation = false; // we don't elgamal table if no ssu, unless it's specified explicitly
-		i2p::crypto::InitCrypto (precomputation, aesni, avx, forceCpuExt);
+		i2p::crypto::InitCrypto (precomputation, aesni, forceCpuExt);
 
 		i2p::transport::InitAddressFromIface (); // get address4/6 from interfaces
 

libi2pd/CPU.cpp

@@ -1,58 +1,58 @@
 /*
-* Copyright (c) 2013-2020, The PurpleI2P Project
+* Copyright (c) 2013-2023, The PurpleI2P Project
 *
 * This file is part of Purple i2pd project and licensed under BSD3
 *
 * See full license text in LICENSE file at top of project tree
 */
 
 #include "CPU.h"
-#if defined(__x86_64__) || defined(__i386__)
-#include <cpuid.h>
-#endif
 #include "Log.h"
 
+#if defined(_MSC_VER)
+#include <intrin.h>
+
 #ifndef bit_AES
-#define bit_AES (1 << 25)
+	#define bit_AES (1 << 25)
 #endif
-#ifndef bit_AVX
-#define bit_AVX (1 << 28)
 #endif
 
-
 namespace i2p
 {
 namespace cpu
 {
 	bool aesni = false;
-	bool avx = false;
 
-	void Detect(bool AesSwitch, bool AvxSwitch, bool force)
+	inline bool cpu_support_aes()
 	{
-#if defined(__x86_64__) || defined(__i386__)
-		int info[4];
-		__cpuid(0, info[0], info[1], info[2], info[3]);
-		if (info[0] >= 0x00000001) {
-			__cpuid(0x00000001, info[0], info[1], info[2], info[3]);
-#if defined (_WIN32) && (WINVER == 0x0501) // WinXP
-			if (AesSwitch && force) { // only if forced
+#if (defined(_M_AMD64) || defined(__x86_64__)) || (defined(_M_IX86) || defined(__i386__))
+#if defined(_MSC_VER)
+		int cpu_info[4];
+		__cpuid(cpu_info, 1);
+		return ((cpu_info[2] & bit_AES) != 0);
+#elif defined(__clang__)
+#if __clang_major__ >= 6
+		__builtin_cpu_init();
+#endif
+		return __builtin_cpu_supports("aes");
+#elif defined(__GNUC__)
+		__builtin_cpu_init();
+		return __builtin_cpu_supports("aes");
 #else
-			if ((info[2] & bit_AES && AesSwitch) || (AesSwitch && force)) {
+		return false;
 #endif
-				aesni = true;
-			}
-#if defined (_WIN32) && (WINVER == 0x0501) // WinXP
-			if (AvxSwitch && force) { // only if forced
 #else
-			if ((info[2] & bit_AVX && AvxSwitch) || (AvxSwitch && force)) {
+		return false;
 #endif
-				avx = true;
-			}
+	}
+
+	void Detect(bool AesSwitch, bool force)
+	{
+		if ((cpu_support_aes() && AesSwitch) || (AesSwitch && force)) {
+			aesni = true;
 		}
-#endif // defined(__x86_64__) || defined(__i386__)
 
 		LogPrint(eLogInfo, "AESNI ", (aesni ? "enabled" : "disabled"));
-		LogPrint(eLogInfo, "AVX ", (avx ? "enabled" : "disabled"));
 	}
 }
 }

libi2pd/CPU.h

@@ -1,5 +1,5 @@
 /*
-* Copyright (c) 2013-2020, The PurpleI2P Project
+* Copyright (c) 2013-2023, The PurpleI2P Project
 *
 * This file is part of Purple i2pd project and licensed under BSD3
 *
@@ -14,9 +14,8 @@ namespace i2p
 namespace cpu
 {
 	extern bool aesni;
-	extern bool avx;
 
-	void Detect(bool AesSwitch, bool AvxSwitch, bool force);
+	void Detect(bool AesSwitch, bool force);
 }
 }
 

libi2pd/Config.cpp

@@ -193,7 +193,7 @@ namespace config {
 		options_description precomputation("Precomputation options");
 		precomputation.add_options()
 			("precomputation.elgamal",
-#if defined(__x86_64__)
+#if (defined(_M_AMD64) || defined(__x86_64__))
 				value<bool>()->default_value(false),
 #else
 				value<bool>()->default_value(true),
@@ -308,7 +308,7 @@ namespace config {
 		options_description cpuext("CPU encryption extensions options");
 		cpuext.add_options()
 			("cpuext.aesni", bool_switch()->default_value(true),                     "Use auto detection for AESNI CPU extensions. If false, AESNI will be not used")
-			("cpuext.avx", bool_switch()->default_value(true),                       "Use auto detection for AVX CPU extensions. If false, AVX will be not used")
+			("cpuext.avx", bool_switch()->default_value(false),                      "Deprecated option")
 			("cpuext.force", bool_switch()->default_value(false),                    "Force usage of CPU extensions. Useful when cpuinfo is not available on virtual machines")
 		;